Answer

Which of the following could be considered the most recent common ancestor of living tetrapods

A) a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
B) an armored, jawed placoderm with two pairs of appendages
C) an early ray-finned fish that developed bony skeletal supports in its paired fins
D) a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes
E) an early terrestrial caecilian whose legless condition had evolved secondarily


Answer: A